The present invention generally relates to an apparatus for removing solids from liquid flow streams, and more particularly, to an improved bar screen apparatus for such purpose.
Screens comprising a plurality of bars in closely spaced side-by-side relation so as to define a plurality of narrow elongated flow openings having a width narrower than the width of solid materials to be screened are commonly utilized in a variety of processing systems for separating solid materials from a liquid flow stream. Typical applications include waste treatment systems for removing solid waste materials from a liquid stream, fruit and vegetable washing systems for removing the cleaned fruit and vegetables from the liquid stream in which they are washed, and food processing operations for removing potato peelings, fruit skins and the like from the liquid processing stream. Such conventional bar screens, however, have the disadvantage that solids of any length, having a width narrower than the width of the spacing between the bars, can pass through the screen, and thus, either contaminate the downstream processing line or require further screening or filtering of the flow stream. When a screen is designed with more closely spaced bars in an effort to minimize such undesirable passage of solids through the screen, such screens have been found to unduly restrict the liquid flow, resulting in increased head losses in the system. Conventional screens have experienced further problems in connection with the efficient removal of solids that adhere and accumulate around the screen bars during the screening process.